I've read in books that you're supposed to empty one breast when you're breastfeeding before giving the other breast to the baby. My query is how do you know when your breast have been emptied. Even when my baby has sucked on my breast for half hour and spits out my nipples, when I squeeze my nipples, milk still comes out so I'm not sure whether my breast has been emptied out or not. I'd appreciate any advice, thanks!